Rangrim(9) you know that cistern is another word for well.
You also remember the book you found was titled Moonlight Dance.
Erani and Alex, (nat 20, 20) you know that while both cisterns and water wells provide water supply, there's a difference between how they do so. Water wells tap into underground water, and consumers have to use a pump or a bucket to draw water from below. Meanwhile, cisterns are containers found either aboveground or underground and need to be filled by rain water or transport from a well.
You also know that most people simple use the words interchangeably.